What started with a prospector discovering a few bones protruding from the Tropic Shale of Utah has ended seven years later with Rebecca (Schmeisser) McKean ’04 (Geology) identifying a new species of prehistoric marine reptile. A paper on her discovery appeared in Cretaceous Research in November.The plesiosaur, named Dolichorhynchops tropicensis, swam the waters covering the western U.S. some 90 million years ago. “It lived at the same time the dinosaurs did,” McKean says.

McKean spent two weeks in Utah with a field crew during summer 2005 excavating one of the two specimens she used to identify the species. “Once we started digging, it was almost a complete skeleton, which was really exciting,” McKean says. “You knew this was the first time anyone was seeing it since it fell to the bottom of the [Cretaceous] seaway.”

McKean began describing and preparing that specimen as part of her master’s research at Northern Arizona University. She continued her research while she earned her Ph.D at the University of Nebraska and joined the faculty at St. Norbert. Piecing the fossils together in the lab took nine months. In the course of that process, McKean made an even more exciting discovery.

“There are a lot of characteristics on the bones that are different from anything we’ve seen before,” McKean says. From there, she focused on proving that these characteristics called for the naming of a new species.

“It’s a tricky process, and it’s a long one,” McKean says.

Two paleontologists who reviewed her findings initially disagreed with them. In the end, though, McKean’s research convinced colleagues that Dolichorhynchops tropicensis indeed stood apart from other species.

March 22, 2012

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